I'm with you up to a point here. I would have no problem with individuals going out and killing snakes to eat (as long as it's something common), and as long as it's dead, why not make use of every possible part of it, rather than let things go to waste? I wouldn't be too upset about the roundups if I thought that most of the meat was being eaten, and none of the snakes were killed JUST for skins or suveneirs, but I'm not convinced that's the case.
On the other hand note that in most states you are strictly forbidden to sell any part of the animals you kill during a regulated hunting season. It all has to be for personal use. Imagine an event where they hauled in 1,000 deer, skinned them, and mounted the antlers to sell...
The fact that snakes happen to be my favorite animal doesn't give me any more right to complain about people killing them. I'm not going to stop feeding mice to my snakes because people keep them as pets, and I don't expect rat keepers to go ballistic when city workers in New York lay poison for the rats there. As hot keepers, I think we have to be a little more realistic...
I'm sure I'm rambling now, but I think there's a point in there somewhere...